This invention related to apparatus and methods for processing signals, for example, signals used for communication or control purposes. It is particularly applicable to processing signals which can consist of a plurality of components each representative of an aspect of a physical entity and the invention provides means for improving the information content or reducing the uncertainty of such signals.
Signal processing systems are known which process signals consisting of a plurality of components in accordance with predetermined information about relationships between the components. So-called "artificial intelligence" systems employ processors which represent known relationships in some form of rule representation and apply the rule representation to an input signal to produce an output signal having an enhanced information content. Conventionally, the rule representation may contain a large number of logical relations between the possible components of the input signal (which, generally speaking, represent known information about a physical entity) and a searching process is carried out through the rule representation in an attempt to derive further relations and information. During the searching process further rules may be established and a large amount of information may have to be stored concerning the results of the application of individual rules already visited. Thus, a problem with conventional systems is that storage requirements may become very large. This has proved a disadvantage particularly when attempting to implement conventional systems in small-scale processing apparatus, such as microcomputer systems. A considerable amount of effort has also been devoted to rule searching strategies in an attempt to find techniques for rapidly arriving at the required information, but none of the known techniques are entirely satisfactory.
Therefore in view of the above, it is a primary object of the present invention to provide a signal processing apparatus and method, particularly of the artificial intelligence type, which may be operated using substantially reduced memory requirements than existing systems.
It is a further object of the present invention to provide a signal processing apparatus and method, particularly of the artificial intelligence type, which has a high execution speed.
It is a further object of the present invention to provide a signal processing apparatus and method which may be used for real time process or system control.